1. Field of the Invention
The present invention relates to a media dispenser. More particularly, the present invention relates to a media pickup apparatus for a media dispenser, capable of discharging stored media from a media cassette by separating the media sheet by sheet.
2. Description of the Related Art
In the present specification, the term “media” refers to sheets of material, such as bank notes, checks, tickets, certificates, etc. The term “media dispenser” refers to an apparatus which automatically supplies such media according to a customer's demand.
FIG. 1 shows a media cassette 1 and a structure for drawing media out of the media cassette 1, which are employed in an automatic media dispenser, in accordance with the related art. The media cassette 1 is installed in the automatic media dispenser. Herein, the media cassette 1 may be either integrated with, or separately formed from, the automatic media dispenser.
Media m are arranged and stacked in the media cassette 1. In the media cassette 1, the media m are pushed toward a discharge port by a push plate 3, so that they are located in tight contact with each other. The push plate 3 is biased or supported by a spring 5 so as to push the media. The spring 5 provides an elastic force which enables the push plate 3 to push the media.
Each sheet of the media, pushed toward the discharge port by the push plate 3, comes into tight contact with a pickup roller 7 before passing through the discharge port. The pickup roller 7 is located at one end of the media cassette 1, comes into contact with and separates each sheet of the media in the media cassette 1, and then moves the separated sheet out of the media cassette 1. The pickup roller 7 may be formed either integrally with the media cassette 1, or separately from the media cassette 1, in the automatic media dispenser.
A feed roller 9 and a contra-roller 10 are disposed close to and opposed to, each other, so as to promote separation of each sheet of the media from another stacked sheet and to transfer the separated sheet. That is, the media are separated and transferred one sheet at a time by the feed roller 9 and the contra-roller 10, while each sheet passes through a gap between the feed roller 9 and the contra-roller 10 rotating in the same direction. Each sheet of the media having passed through the gap between the feed roller 9 and the contra-roller 10 is transferred by a feed roller or a belt provided at a delivery module (not shown).
However, the aforementioned related art has the following drawbacks. The contact force of the media m against the pickup roller 7 caused by the push plate 3 may vary depending on an amount of media m stored in the media cassette 1. Accordingly, a frictional force between the media m and the pickup roller 7 can vary depending on the amount of media m stacked in the media cassette. Because of the varying frictional force, often the pickup roller 7 cannot precisely pick the media m up, sheet by sheet. In addition, if the spring providing the elastic force for biasing the push plate 3 towards the pickup roller 7 has a fault due to a long-term usage thereof, or if an original elastic force of the spring changes due to external or internal factors thereof, a performance of the pickup roller 7 in singularly picking up sheets of media may be deteriorated.